Preparing bentonite compositions



Patented Aug. 23, 1932 UNITED STATES PATENT OFFICE.

imam narrnnm, or CHICAGO, rumors, nssreuon or one-m! no A. 2. mm!

PREPARING BEHTQNITE COMPOSITIONS 1T0 Drawing.

The present invention relates to the prepa-' ration of bentonite compositions, and more sition containing t particularly to dry compositions containing a soluble electrolyte, such as salt, intimately commingled with bentonite.

It has been proposed to employ, for cleaning purposes, a suspension of bentonite in water containing a suitable electrolyte, such as salt- I For commercial purposes, it is desirable to preparea dry or a proximately dry com oe bentonite and solu le electrolyte which can be sold and shipped without'added water, and which may be admixed with the necessary water for producing the suspension by the consumer. Owing to the tendency of the bentonite to cake and form clay-like, impenetrable masses and to difficulties in admixture, it has not been practical to secure such a composition by mere mechanical mixture of the bentonite and the electrolyte, such as salt, or by dissolving the salt in water and mixing the resulting solution with thebentonite in the ordinary manner. Particularly in the latter case, the bentonite tends to form clay-like lumps or balls of a plastic character and of large size, which are substantially impenetrable and which resist drying to a marked degree. Such lumps'are found to retain their moisture content after weeks of air drying and after days of forced drying by air circulation.

I have found that these diflic'ulties may be avoided, and an intimate mixture of bentonite and an electrolyte, such as salt, made by vthe following process, in which I take advantage of certain uni ue features of be-' havior of bentonite whic I have discovered.

In carrying out my invention, I distribute the bentonite to be employed in making the mixture in a shallow layer, ordinarily 6 to 8 inches in de th, but which may vary from, say, one-hal inch to one foot or eighteen inches. I reparea solution of the electrolyte in water, orming a strong or even saturated solution thereof, so as to minimize the rortion ofwater and facilitate drying. T us, in preparing a mixture containing four parts of salt per one hundred, I may dissolve the four parts of salt in twelve to twenty pTrts Applicationand July as,

of water, and preferablyabout fifteenparts. More dilute solution may be emplo ed, particularly when lower proportions 0 salt rel ative to bentonite are used, since it is desirable to use sufiicient liquid to completely penetrate the mass. The solution of eletrolyt'e is then sprayed or sprinkled over the layer of bentonite to secure "an approximately uniform distribution thereof, either by means of sprays which uniformly and simultaneously spray the entire exposed surface of the layer of'b'entonite or by means of a spray or sprinkler which is moved the exposed surface of the ayer ofbentoni'te to secure uniform distribution of the electrolyte solution. When so applied, the solution of the electrolyte is absorbed by the layerof bentonite, and ;the latter, instead 'of forming impenetrable, clay-like lumps cracks and breaks up into granules or nodules, -a half inch across, and all of which,including the larger nodules, are friable and easily broken into smaller nodules. The granular mass may then be readily dried, either by air drying or by any other suitable means, as by forcing air through the shallow layer of granular material, as

er or in any other suitable apparatus. The dried material, which may then be powdered, can be packed and shipped for use as a deter ent, for example, as described.

t is readily apparent that any other suitable neutral electrolyte, such as potassium' up granular and friable nodules, the pro! progressively over for the most part less thenformed, or by passing the granular material through a rotary-drymay be ashallow portion of the solution bein such as to be completely absorbed by the tonite without soaking the latter.

2. The method of preparing a mixture of 5 bentonite and a soluble electrolyte which comprises s reading the bentonite in a shallow layer, dissolving the electrolyte in water to form a solution, spraying the solution aproximately uniformly over the exposed sur- 19 ace of the layer of bentonite, whereby the solution is absorbed by the bentonite and the latter-breaks up into a granular and friable nodular mass, and dryin the resulting mass, the proportion of the so ution bein such as to be completely absorbed by the ntonite without soaking the latter. i a I 3. The method of forming a bentonite-salt mixture, which comprises spreading the bentonite in a shallow layer, dissolvin the salt in water, and distributing the res ting salt solution uniformly over the surface of the bentonite, whereby the salt solution is absorbed b the later, the proportion of the solution ing'such as to 0 completely absorbed by the bentonite without soakin the latter, and as a result the bentonite brea up to form a mass of granules and friable nodu es.

4. The method of forming a bentonite-salt mixture which com rises spreading a layer of bentonite to a thickness of six to eight inches, dissolving salt in water in the proportions of four parts of salt and fifteen parts of water to each onehundred parts of ben- 35 tonite, spraying the resultin salt solution uniformly over the surface 0 the bentonite I layer, whereby the salt solution is dissolved by the latter and the bentonite mass breaks up'into granules and friable nodules, and

drying the resulting mass.

In testimony whereof I have hereunto set my hand this 21st da of Jul 1930. HERMA BATT RMAN. 

